Method of treating wood-tar oil



Patented Oct. 20, 1925.

PATENT OFFICE...

AUGUSTUS E. MAZE, OF EAST ORANGE, NEW JERSEY, ASSIGNOR TO ELLIS-FOSTER'COM- PANY, OF MONTGLAIB, NEW JERSEY, A CORPORATION OF NEW JERSEY.

METHOD OF TREATINGWOOD-TAR OIL.

No Drawing.

To all whom it may concern:

Be it known that I, AUeUsTUs E. MAZE, a citizen of the United States, and a resident of East Orange, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Methods of Treating \Vood-Tar Oil, of which the following is a specification.

This invention relates to a method of treating wood tar oil and especially distillates of this oilin order to obtain improved solvents for nitrocellulose and for other purposes. Wood tar oil is known under a variety of names such as wood oil (not to be confused with tung oil), hard wood oil, chemical, oil, light chemical oil or the like. It is an oil of somewhat variable composition obtained from wood tars resulting from the various operations of wood distillation in connection with the manufacture of wood alcohol and acetate of lime and the rectification of wood alcohol. These tars, singly or combined, when distilled yield distillates boiling from say i0 G. and upwards.-

The odor of the distillates from tars from any of these sources is very disagreeable due to empyreumatic and other bodies and in the present invention it is an object to modify the odor to eliminate its disagreeable characteristics and provide a solvent vehicle having an agreeable odor so that it may be used in dissolving nitrocellulose for making lacquers and various other purposes without the objections arising from the use of the untreated wood tar oil distillate. The raw distillates are liable to discolor and on prolonged standing form gummy or resinous substances which oftentimes is objectionable. This difficulty may be obviated by my process a vehicle substantially free from tendency to discolor and resinify being obtained.

The invention is based on the treatment of the wood tar oil or preferably selected distillates with an appropriate oxidizing agent. In the preferred form of the invention I employ bleaching powder as the oxidizing agent because thereby I secure a limited amount of chlorination which I believe to be beneficial. A distillate starting to boil between 40 and 60 C. and boiling up to about 125 or 130 C. is preferable for my purposes, and the first step in the operation may be that of distilling the wood tar oil up AppIication filed March 27, 1924. Serial No. 702,560.

Having obtained a distillate preferably boiling within the range specified I may dry it by treatment with calcium chloride and treat it with dry bleaching powder using 1 part of the latter to 4: or 5 parts of the distillate. The operation may be carried out in the cold or at slightly elevated temperatures, say between 30 and 50 C. The bleaching powder should be added gradually with agitation as the reactionmay become violent if the entire charge of bleaching powder is introduced into the oil at one time. Reaction is allowed to take place and in this case owing to the use of the dry bleaching powder a considerable degree of chlorination may occur. The reaction is complete very soon after all the bleaching powder has been added but agitation may continue for a period of 4 or 5 hours. The reaction is exothermic and the time of treatmentwill vary to a considerable extent with the size" of the batch, cooling being necessary in some cases.

The following procedure illustrates my process in a detailed way but it should be understood that I do not wish to be limited to such details as are furnished for illustrative purposes.

A sample of wood tar oil which was reddish-brown to reflected light and a claret red to transmitted light and which was not of a viscous character was distilled. Distillation began at 46 C. and a cut was made at 130 C. This fraction, 46-130" (3., was practically free from phenolic substances and oils which on treatment by my process become poor solvents for nitrocellulose. The distillate is light yellow but on standing becomes brown and gradually darkens. Calcium chloride was added to the distillate and allowed to stand in contact therewith for 24 hours. The distillate was then decanted.

250 c. c. of the distillate was treated with grams of bleaching powder, that is ordinary commercial bleaching powder containing some moisture. No water was added to the bleaching powder, it being used in a pulverulent form. The bleaching powder was added in 10 gram portions over a period of 2 hours, the distillate being stirred meanwhile. In the beginning the temperature of the distillate was 12 C. but at the end the temperature had risen to 37 C. owing to heat of reaction. The light yellow color of the distillate had changed to a yellow-orange. On filtration 185 c. 0. were collected and on distillation 162 c. c. boiling from 76 140 C. were obtained. The distillation was carried out at atmospheric pressure and at 135140 (1, there was some indication of aburnt odor hence the distillation was stopped. Distillation of the higher boiling fractions should be carried out under reduced atmospheric pressure. During the distillation =1 0. c. of water separated.

I have found that by making a cut at 130 C. in the distillation of the raw wood oil the distillate obtained up to 130 C. when treated with bleaching powder yields a good solvent for nitrocellulose. On the other hand if the distillate above 130 C. of the raw wood oil is treated with bleaching powder a liquid is obtained which although it may dissolve cellulose on drying shows marked indications of segregation. This observation forms one feature of my invention.

I may add that in the final distillation of the product which has been treated with bleaching powder I prefer to use a column still in order to rectify carefully. Also prior to or subsequent to rectification the distillate may be treated with an alkali to remove any traces of hydrochloric acid or chlorine material which would have an acid effect. The final rectification if desired may take place over quick lime.

In place of bleaching powder I may use any other equivalent substance.

VVh-at I claim is 1. The process of making a nitrocellulose solvent from wood tar oil which comprises agitating a distillate thereof, boiling 'up to 130 6., with bleaching powder whereby a product of improved odor and good solvent properties for nitrocellulose is obtained.

2. The process of treating wood tar oil to obtain a solvent suit-able for dissolving nitrocellulose which comprises distilling said oil to obtain a distillate boiling up to about 130 C. which is substantially free from nitrocellulose non-solvents of higher boiling point, drying and reacting on such distillate with bleaching powder, separating the oxidized distillate'and redistilling; whereby a light colored to water-white distillate having marked solvent properties for nitrocellulose is obtained.

3. The process of treating wood tar oil to obtain a solvent suitable formaking films of nitrocellulose which comprises distilling the raw oil to obtain a distillate boiling up to about 130 6., reacting on the distillate with bleaching powder and redistilling; whereby a light colored distillate is obtained having marked solvent properties for nitrocellulose.

GU T S AZE 

